Robert Zubrin's Power and Purpose in Space. Wood, wind, water, coal, oil, gas, and nuclear energy: of those major power sources, only one, nuclear, can work in space. Like it or not, humanity is going nowhere, astronautically speaking, without the power of the atom. Real spaceships must use nuclear power. It's the only practical way of exploring and colonising space. Fission fragment, nuclear salt water, gas core and other exotic reactors are being researched for future missions in light of the Bush administrations new nuclear space initiative. But there is another option that was available to us generations ago and remains to this day the only engine that affords both very high thrust and Isp. A single stage launcher which could reach Pluto and back inside of a year. A simple design that could be scaled up to starship configurations. The concept is known as Nuclear Pulse Rocketry and its feasibility was proven beyond the doubt of the top minds who worked on Project Orion for the 7 years it was financed by the airforce, army and NASA. The initial plan called for manned missions to Mars by 1965 and Saturn by 1970. Jerry Pournelle who was aquainted with the project leader Freeman Dyson is quoted as saying that a large permanent moon base could have been established in a single mission. Back in the 1960's they were working on fission pulse units to bomb around the solar system. Today we can entertain the option of thermonuclear fusion. While steady fusion may turn out to be a pipedream the science of hydrogen bombs is well proven and developed. We can nuke our way to the stars if we want to. We can also colonise the solar system in style and that would be a nice prelude to star travel. Either that or sit on our hands and hope something better comes along. Its already been 36 years since we went to the moon. Me? I'm tired of waiting. I don't believe anything remotely practical will come along that isn't nuclear. Technological advancement requires hands on engineering and competition. We didn't go from steam engines to Ferrari's on a drawing board. We have to use what we have and hope its a stepping stone to increasingly more impressive generations of vehicles. The alternative is to do nothing but wish for some perfect concept that may not materialise. Atleast not until the window of opportunity is lost. How long advanced civilisations capable of spaceflight endure is a question open to much conjectural debate. Our societies are quite fragile and our technology requires a large specialised workforce to maintain it. We may even lose our lust for space. If there was ever enough determination to begin with. KK EDIT: Try in this thread.